Actuating mechanism for aerodynamic surfaces



ACTUATING MECHANISM FOR AERODYNAMIC SURFACES Filed Aug. 21, 1943 2Sheets-Sheet 1 INVENTOR JOHN NOYES JR.

BY I

ATTORNEY June 10, 1947. J NOYES, JR 2,422,035

ACTUATING MECHANISM FOR AERODYNAMIG SURFACES I Filed Aug. 21, 1943 2Sheets-Sheet 2 a: gg llimim INVENTOR. aox-m NOYES JR A TTORNE Y PatentedJune 10, 1947 ACTUATING MECHANISM FOR, AEBQ- DYNAMIC SURFACES.

John Noyes, Jr., University City, Mo., assignor to. The Gurtiss-WrightCorporation, a cornmration of Delaware Application August 21, 1943,Serial No. 499,746

Claims. 1.

This invention relates to improvements in airplane control systems andmore particularly to an improved and novel arrangement of an actuatingmechanism for aerodynamic surfaces.

In certain arrangements or configurations of main supporting surfacesfor airplane, and especially in those cases in which the main surface isgenerally characterized as having a high degree of sweep back angle, itis necessary to provide some means for arrangement for maintaining thelongitudinal stability characteristics of the airplane when it is foundnecessary to utilize high lift devices such as flaps. Moreover, it isparticularly important in such an arrangement that longitudinalstability or adverse pitching moments be closely controlled duringlanding or take-off operations of the airplane, since at that time anyadverse disturbance of the direction of the airplane becomes a criticalfactor and may impair the safe operation thereof. Therefore,

the present invention constitutes what is believed to be an importantimprovement in the arrangement of. control surfaces in an airplane ofthe above type and especially when high lift devices or flaps are in.use, for the pitching moment produced thereby is automaticallycompensated by the concurrent upward deflection of the usual lateralcontrol surfaces such as ailerons.

Accordingly, an important object of the present invention is to providean interconnection between the usual lateral control system and anysuitable high lift device for the purpose of trimming the airplane inits longitudinal attitude.

Another object is to provide an operating system for carrying out theabove stated purposes and. in which the lateral control system is freefor normal operation in the usual manner.

Further objects of the present invention reside in the provision ofmeans for automatically moving the high lift device or flaps into adeflected or down position and at the same time, moving the lateralcontrol surface, for example ailerons, into. an upward deflectedposition to counteract and. substantially cancell out pitching momentsproduced by the. flap devices.

Other objects and advantages to be attained herein. will: be pointed outand described in the following specification covering a preferredembodiment of the present invention when considered in view of theaccompanying drawings in which:

1 is a general schematic view of the principalparts and elements of thepresent invention arranged: on a supporting" surface or wing;

Fig. 2 is a partial sectional elevation particu- 2 larly illustratingthe driving mechanism and its operative connection with a flap device ofsplit typ Fig. 3 is a further sectional detail of the aileron mechanismand its relation with respect to the wing surface,

Fig. 4 is a plan view of the diiferential mechanism showing furtherdetails thereof, and

5 is a front elevational view of the differential mechanism of Fig. 4.

Referring now in particular to Fig. l, the general arrangement of theseveral parts and elements of the present invention is clearlyindicated, and as thereshown, includes a high lift device or flap I0arranged to be pivotally deflected by a motor and gear unit H. A lateralcontrol surface or aileron I2, is positioned along the trail-ing edgeofthe wing or main supporting surface l3, and a differential levermechanism I4 is conveniently arranged with respect to the aileron andwith respect to the motor and gear unit II, in order that a suitableinterconnecting means as a chain or combination chain and cable l5 maybe disposed therebetween for operation of a secondary control devicelater described. The

differential mechanism I4 also includes means for the connection ofprimary control cables I6, which cables are suitably mounted to ride onpulley units I1 and are rigged with the usual pilots control column (notshown), hence the aileron can be utilized for importing lateral controlto the airplane.

Referring now to Fig. 2, a preferred arrangement for mounting the flapIll and for connecting the flap with the operating motor and gear unit 1I is shown to advantage. The interconnection between the flap andoperating motor includes a horn ill, a connecting member or arm l9, anda crank arm 20 operatively carried in the motor-gear unit I I. In thisarrangement the operating motor and gear box may be suitably bolted orotherwise secured by the provision of flange ears 2l= to a verticalmember of the'wing structura-suoh as a spar or beam; indicated at 22.The crank arm or operating member 20 is mounted on a shaft Hand isadapted to be turned through a'predetermined angle so the flap l0 willbe moved through approximately 45 between its closed or up position andits down position. The dotted line position of the arm 2!), connectingrod l9, and horn l8, clearly indicate the amount of angular deflectionand motion necessary for this purpose. While it is not important to thepresent invention to show the exact or a particular arrangement of thegearingto be contained in the unit II, it is contemplated that anysuitable system of reduction gears may be employed between the drivingmotor such as the one indicated at 24 Fig. 1, and the shaft 23 foroperating arm 20. The particular novelty claimed for this operating unitII is exemplified in the further arrangement and addition of a drivingshaft '25 and sprocket gear 26, fixedly secured to the shaft. Thislatter driving shaft 25 is arranged substantially normal to the flapoperating shaft 23 in order that the driving chain or chain and cablecombination may extend spanwise of the wing for convenient engagementwith a secondary control or an actuator and sprocket 2'! which will bedescribed in more detail in connection with the differential leverdevice shown to particular advantage in Figs. 4 and 5. The motor isessentially of high speed type and therefore requires a considerablegear reduction for each of the operating shafts 23 and 25. A requirementof this gear reduction is that the flap Ill be deflected downwardlythrough an angle of approximately 45 and that concurrently with thisflap motion, the chain drive means 5 operate actuator 21 to produceapproximately a upward deflection of the aileron surface |2. It is, ofcourse, understood that the amount of deflection of the fiap l0 and thecounter-deflection of the aileron l2 will be governed by certain designfeatures peculiar to each installation and that for the presentinvention, the above indicated degrees of movement for both the flap andthe aileron apply to best advantage in an arrangement shown in Fig. 1.Though not shown, any suitable type of double acting limit switch,responsive to the movement of flap l0, may be inserted in the electricsystem for motor 24. This limit switch should act to stop the motor uponthe flap reaching the limits of its travel, both up and down.

Referring now to Fig. 3, there is indicated one suitable arrangement forhingedly mounting the aileron member l2 on a pivot shaft 30, whichextends longitudinally thereof and is suitably mounted in fixed bearingmembers (not shown) carried by an adjacent structural part of the wingI3. A suitable horn 3| is attached to the inner margin of the aileron l2and the same is provided with a boss or ear 32 for the attachment of apush-pull rod 33, the latter member being connected with thedifferential lever mechanism l4. There is also shown in Fig. 3 theposition of actuator 21 relative to the aileron and its securement tothe structural member or spar 22.

A more detailed showing of the differential mechanism l4 will be foundin Figs. 4 and 5. As there shown, the differential mechanism includes apair of substantially vertically spaced supporting arms 34 each of whichis pivotally mounted at one end in a suitable bracket element 35 whilethe opposite end of each of these arms 34 is secured in spaced adjacenceso that the operating arm 36 of the actuator member 21 may be pivotallypositioned therebetween. A bell crank member or element 31 is arrangedbetween the supporting arms 34 and is also pivotally mounted on a shaft38, the latter shaft serving as the common pivot for each of the arms 34with respect to the bracket 35. Thebell crank member or element 3'! isformed to provide a pair of control cable arms 39 and 40 and anoperating arm 4|. The arrangement and relation of the several arms onthe bell crank 31 is such that cable arms 39 and 40 project oppositelytherefrom whileoperating arm 4| is angularly arranged at substantially aposition from each of the cable arms. The bell crank 31 is furtherarranged so that the cable arms 39 and 40 respectively are positioned atthe lower and upper extremities thereof, while the operating arm 4| isdisposed intermediately thereof. Moreover the bell crank member 31 maybe conveniently formed as an integral member, however, it is equallypossible to construct the same of separate parts which are assembled ina fixed manner. A second bell crank or transfer member 42 is pivotallymounted in the space between supporting arms 34 and is arranged at asuitable position intermediate the ends of these supporting arms, forpivotal movement about pivot elements 43. The transfer member 42 isprovided with a single operating arm 44, the outer end of which isprovided with a pair of suitable pivotal connections for a connectinglink 45 and the push-pull rod 33. Link 45 forms the interconnectionbetween bell crank arm 4| and transfer member 42 as clearly indicated inFig. 4. A suitable cable member [6 extends from the cable arms 39 and 40respectively to the pilots control column (not shown) located in thecockpit or other position in the fuselage.

Considering first the normal operation of this differential levermechanism I4, it will be understood that the pilot may move the controlcolumn in a side to side manner, and that tension thereby will beexerted in either one or the other of the cables I 6 in the usualmanner. If we assume, for the purpose of this description, that a pullis exerted on cable i6 connected to the cable arm 39, the bell crank 3'!will be moved in a clockwise direction as viewed from Fig. 4. Angulardisplacement of cable arm 39 will cause operating arm 4| to move inaccordance therewith and, in turn, link 45 will exert a clockwiserotational force on the intermediately disposed transfer member orsecondary bell crank 42. The motion of the latter bell crank 42 will betransmitted to push-pull rod 33 through its connection with the arm 44as before described. The backward or rearward movement of push-pull rod33 will effect an upwardly directed movement or deflection of aileronsurface I2, and the degree of deflection will be determined by theextent of clockwise rotation of bell crank 37. It will be observed thatthe differential lever mechanism utilizes the principle of a pantographin that pivot points 38, 43, and the pivotal connections at each end oflink 45 form the corners of a parallelogram lever system. In thispantograph arrangement, the supporting arms 34 are relatively fixed withrespect to the remainder of the system and therefore displacement of thearm 4| will result in substantially the same displacement of the arm 44provided the two arms 4| and 44 are of equal lengths.

The secondary controller or actuator device 21 which is directly subjectto operational control by the motor gear unit through the chain drive I5is suitably mounted in a supporting bracket 46. This actuator device 21includes a sprocket wheel or gear 41 mounted for rotation on a bearingcarried by bracket 46 and operatively related with an internallypositioned screw jack 48 and integrally formed operating arm 36. Theoperation of member 27 is such that upon its rotation by movement of thechain drive [5, the screw jack and operating arm will be threadedinwardly or outwardly without relative rotation as dictated by thedirection of rotation of the drive shaft 25, Fig. 2. Since operating arm36 of this secondary controller 21 is directly and pivotally connectedwith the free end of the supporting arms 34 of the differential levermechanism l4, it will be seen that angular displacement of thesupporting levers 34 about pivot shaft 38 will result. Hence theactuator member 21 will serve angularly and bodily to displace thedifferential lever system through any desired degree of displacement.Assuming that the control cables [6 are at that time fixed so as toimmobilize the pantograph system and especially the transfer member 42,it will be evident that bodily displacement of the differential levermechanism M will result in an angular displacement of the aileronsurface l2 through interconnection of the push-pull rod 33. Hence asecondary control over the position of the aileron is establishedwithout interference with the primary or pilots control through cablesI6.

The foregoing description covers a preferred arrangement of operatingparts and elements for carrying out the stated objects, and is believedto exemplify a very simple yet efficient and trouble-free arrangement ofoperating mechanisms for the rapid and positive angular adjustmentbetween the flap l and the aileron l2. As before stated, it is ofmaterial importance especially in an airplane configuration in which themain supporting surface is characterized by a high degree of sweep-backangle, that the longitudinal stability thereof be positively andadequately provided for at such times as it becomes necessary to utilizehigh lift devices such as flaps or the like, An important advantagewhich is attained in the present invention is evidenced in thearrangement of the differential lever device M, which permits at alltimes the normal and free operation of the aileron l2 for attaininglateral control of the airplane and at the same time, for permitting acertain and advantageous amount of angular deflection to be imposedthereon for the purpose of trimming the airplane in its longitudinalattitude. Hence the aileron member I2 serves in its usual capacity as alateral control member and also as a trimming device when employed incombination with high lift devices or flaps.

It is apparent that the above described embodiment of the presentinvention discloses an efficient and simple structure and one which willattain each and every one of the objects herein set forth; but it is tobe understood, however, that certain modifications, alterations, andother minor changes may be made in the several parts and elements hereofwithout departing from the spirit and intended scope of the invention asdefined by the claims hereinafter appended.

What is claimed is:

1. In a control mechanism for operating a device or agency, a firstcrank lever, a second crank lever, a link pivoted to and interconnectingsaid first and second crank levers, a push-pull rod connected to saidsecond crank lever and to the device or agency to be operated, means forangularly adjusting said first crank lever to effect a longitudinalchange of position of the said push-pull rod to operate the device oragency, relatively fixed means for supporting the said first and secondcrank levers in a pivotal manner, and means for moving the fixedsupporting means to superpose a longitudinal change of position of saidpush-pull rod irrespective of the change of position of said push-pullrod by said adjusting means.

2. In a control system for the simultaneous actuation of differentaerodynamic surfaces, a gear unit having a first and second operatingshaft, a crank on the first shaft, means operatively connecting thecrank with an aerodynamic surface, a rotary element on the secondoperating shaft, a differential mechanism associated with a differentaerodynamic surface for effecting independent operation thereof, arotary controller unit operatively related with a differential mechanismand adapted to be driven by the rotary element on the second shaft, andpower means for said gear unit whereby the crank will be moved to effecta displacement of the associated aerodynamic surface and the rotarycontroller unit will be operated to effect displacement of thedifferential mechanism and consequently a displacement of the associateddifferent aerodynamic surface.

3. In an airplane control system, an aileron surface, flap means, adifferential mechanism mounted for swinging movement and including acrank system carried thereby, means connecting said crank system withthe aileron surface, means for actuating said crank system to move saidaileron, a power unit operatively associated with said flap means formoving the same, and means connecting said power unit with saiddifferential mechanism whereby said differential mechanism may be movedsimultaneously with movement of said flap means to effect concurrentmovement of said aileron irrespective of the action of said means foractuating said crank system.

4. In an airplane, an aileron, a flap, a differential mechanism mountedfor swinging movement and including a crank system operatively carriedthereby, a push-pull rod connecting said crank system with said aileron,means actuating said crank system to move said aileron, means for movingsaid flap, and means operated by said flap moving means for swingingsaid differential mechanism in a manner to effect a' longitudinal changeof position of said push-pull rod and hence movement of said aileron.

5. In an airplane, an aileron, a flap, a differential mechanism mountedfor swinging movement and including a crank system operatively carriedthereby, a push-pull rod connecting said crank system with said aileron,cable means for actuating said crank system, a motor operated unit formoving said flap, and means operatively interconnecting the motoroperated unit and said differential mechanism whereby operation of saidmotor unit to effect movement of said flap will be accompanied by asimultaneous swinging movement of said differential mechanism and hencemovement of said aileron.

JOHN NOYES, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,992,157 Hall Feb. 19, 19352,172,289 Munk Sept. 5, 1939

